The ultimate goal of pain research must be to determine the most effective treatment for a particular patient. Pain is a multidimensional mixture of sensory, emotional, cognitive and other experiences, the sum total of which may be termed "global pain". To treat pain, we must measure pain. Thus, the immediate goals are: (i) to determine the number of dimensions of both verbal and physical global pain; (ii) to identify and compare the sensory, emotional and other characteristics of these dimensions; and (iii) to find the location or "address" of each individual in these global pain spaces. The knowledge obtained in these studies on healthy volunteers will aid differential diagnosis, as well as permit treatment to be tailored towards the proper sensory, emotional or other aspects of pain. An important contribution of these studies is that global pain spaces will be obtained to two types of "stimulus objects": verbal (sensory and emotional) descriptors, and physical (electrical and thermal) stimuli. These two global pain spaces approximate a pain patient describing his pain. The number of dimensions and the configuration of the stimulus objects in the group stimulus space will be determined by the individual differences scaling technique (INDSCAL), and the meaning of these dimensions will be established by the property or preference mapping technique (PREFMAP). In addition, the subject weight spaces, which measure the relative "saliency" of each INDSCAL dimension to each individual, will be obtained. Further, the individual attribute vectors obtained from PREFMAP will yield information on the meanings attached to these dimensions, as well as locate the individual. In the first block of experiments, INDSCAL and PREFMAP spaces will be obtained for (a) three sets of physical stimuli: electrical, thermal, and mixed electrical-thermal, and (b) three parallel sets of verbal descriptors of these sensations and emotional experiences. In the second block of experiments, the effect of (a) continuous pain and (b) fear/anxiety without pain on the INDSCAL and PREFMAP spaces will be examined. In the third block of experiments the effect of (a) an analgesic (fentanyl) and (b) an anxiolytic (diazepam) on the INDSCAL and PREFMAP spaces will be compared. The fourth block of experiments will compare these INDSCAL and PREFMAP spaces with measures obtained from signal detection theory, and magnitude estimation techniques, as well as standard measures of anxiety etc.